Use git URL to allow linux static build with nix

Author: jeffhappily

stack.yaml

@@ -24,7 +24,7 @@ extra-deps:
 - Cabal-3.0.0.0@rev:0
 - hpack-0.33.0@rev:0
 - http-download-0.2.0.0@rev:0
-- github: snoyberg/filelock
+- git: https://github.com/snoyberg/filelock.git
   commit: 97e83ecc133cd60a99df8e1fa5a3c2739ad007dc
 - pantry-0.4.0.1@rev:0
 - casa-client-0.0.1@rev:0